Image Classification (Single Label)

Use an Amazon SageMaker Ground Truth image classification labeling task when you need workers to classify images using predefined labels that you specify. Workers are shown images and are asked to choose one label for each image.

You can create an image classification labeling job using the Ground Truth section of the Amazon SageMaker console or the CreateLabelingJob operation.

Important

For this task type, if you create your own manifest file, use "source-ref" to identify the location of each image file in Amazon S3 that you want labeled. For more information, see Input Data.

Create an Image Classification Labeling Job (Console)

You can follow the instructions Create a Labeling Job (Console) to learn how to create a image classification labeling job in the SageMaker console. In Step 10, choose Image from the Task category drop down menu, and choose Image Classification (Single Label) as the task type.

Ground Truth provides a worker UI similar to the following for labeling tasks. When you create the labeling job with the console, you specify instructions to help workers complete the job and labels that workers can choose from.

Create an Image Classification Labeling Job (API)

To create an image classification labeling job, use the SageMaker API operation CreateLabelingJob. This API defines this operation for all AWS SDKs. To see a list of language-specific SDKs supported for this operation, review the See Also section of CreateLabelingJob.

Follow the instructions on Create a Labeling Job (API) and do the following while you configure your request:

• Pre-annotation Lambda functions for this task type end with PRE-ImageMultiClass. To find the pre-annotation Lambda ARN for your Region, see PreHumanTaskLambdaArn .

• Annotation-consolidation Lambda functions for this task type end with ACS-ImageMultiClass. To find the annotation-consolidation Lambda ARN for your Region, see AnnotationConsolidationLambdaArn.

The following is an example of an AWS Python SDK (Boto3) request to create a labeling job in the US East (N. Virginia) Region. All parameters in red should be replaced with your specifications and resources.

response = client.create_labeling_job(
    LabelingJobName='example-image-classification-labeling-job',
    LabelAttributeName='label',
    InputConfig={
        'DataSource': {
            'S3DataSource': {
                'ManifestS3Uri': 's3://bucket/path/manifest-with-input-data.json'
            }
        },
        'DataAttributes': {
            'ContentClassifiers': [
                'FreeOfPersonallyIdentifiableInformation'|'FreeOfAdultContent',
            ]
        }
    },
    OutputConfig={
        'S3OutputPath': 's3://bucket/path/file-to-store-output-data',
        'KmsKeyId': 'string'
    },
    RoleArn='arn:aws:iam::*:role/*,
    LabelCategoryConfigS3Uri='s3://bucket/path/label-categories.json',
    StoppingConditions={
        'MaxHumanLabeledObjectCount': 123,
        'MaxPercentageOfInputDatasetLabeled': 123
    },
    HumanTaskConfig={
        'WorkteamArn': 'arn:aws:sagemaker:region:*:workteam/private-crowd/*',
        'UiConfig': {
            'UiTemplateS3Uri': 's3://bucket/path/worker-task-template.html'
        },
        'PreHumanTaskLambdaArn': 'arn:aws:lambda:us-east-1:432418664414:function:PRE-ImageMultiClass,
        'TaskKeywords': [
            Image classification',
        ],
        'TaskTitle': Image classification task',
        'TaskDescription': 'Carefully inspect the image and classify it by selecting one label from the categories provided.',
        'NumberOfHumanWorkersPerDataObject': 123,
        'TaskTimeLimitInSeconds': 123,
        'TaskAvailabilityLifetimeInSeconds': 123,
        'MaxConcurrentTaskCount': 123,
        'AnnotationConsolidationConfig': {
            'AnnotationConsolidationLambdaArn': 'arn:aws:lambda:us-east-1:432418664414:function:ACS-ImageMultiClass'
        },
    Tags=[
        {
            'Key': 'string',
            'Value': 'string'
        },
    ]
)

Provide a Template for Image Classification Labeling Jobs

If you create a labeling job using the API, you must supply a worker task template in UiTemplateS3Uri. Copy and modify the following template. Only modify the short-instructions, full-instructions, and header.

Upload this template to S3, and provide the S3 URI for this file in UiTemplateS3Uri.

<script src="https://assets.crowd.aws/crowd-html-elements.js"></script>
<crowd-form>
  <crowd-image-classifier
    name="crowd-image-classifier"
    src="{{ task.input.taskObject | grant_read_access }}"
    header="please classify"
    categories="{{ task.input.labels | to_json | escape }}"
  >
    <full-instructions header="Image classification instructions">
      <ol><li><strong>Read</strong> the task carefully and inspect the image.</li>
      <li><strong>Read</strong> the options and review the examples provided to understand more about the labels.</li>
      <li><strong>Choose</strong> the appropriate label that best suits the image.</li></ol>
    </full-instructions>
    <short-instructions>
      <h3><span style="color: rgb(0, 138, 0);">Good example</span></h3>
      <p>Enter description to explain the correct label to the workers</p>
      <h3><span style="color: rgb(230, 0, 0);">Bad example</span></h3><p>Enter description of an incorrect label</p>
    </short-instructions>
  </crowd-image-classifier>
</crowd-form>

Image Classification Output Data

Once you have created an image classification labeling job, your output data will be located in the Amazon S3 bucket specified in the S3OutputPath parameter when using the API or in the Output dataset location field of the Job overview section of the console.

To learn more about the output manifest file generated by Ground Truth and the file structure the Ground Truth uses to store your output data, see Output Data.

To see an example of an output manifest file from an image classification labeling job, see Classification Job Output.